A gas turbine engine typically includes an augmenter, or afterburner, which produces additional thrust from the engine. Thrust augmentation is particularly useful in military aircraft, which often need brief periods of additional thrust during takeoff, climbing, or combat maneuvers. The augmenter typically is disposed in the exhaust section of the gas turbine engine. The gas flow of the augmenter is circumscribed by an augmenter liner and an augmenter case. The augmenter case is disposed outwardly in a radial direction from the augmenter liner, with a cooling space between them.
Augmenter cases include a cam follower track. During normal use of the gas turbine engine, the cam follower track of the augmenter case becomes worn. The high cost of augmenter cases makes it very desirable to repair the worn area of the cam follower track. Repairing the cam follower track of an augmenter case includes three basic steps: building up the worn area of the cam follower track using a welding process, heat-treating the built-up welded area of the cam follower track to relieve local stress, and machining the welded area of the cam follower track to conform to the desired dimensions.
The cam follower track of an augmenter case has an elongated shape. This elongated shape makes it difficult to provide heat treatment in a uniform manner to the welded area during the second step of the repair process.
Therefore, there is a need in the art for an apparatus to provide localized heat treatment of the welded area of a gas turbine engine component that is being repaired, such as the cam follower track of an augmenter case. It is important that the device provide sufficient heat for the stress-relief process, while also minimizing the amount of heat delivered to areas adjacent to the area being repaired.